This invention relates to a rotary sheet-printing press which includes a register bar provided with a plurality of front lay marks arranged in a series transverse to the direction of advance of the sheets to be printed. The front lay marks serve the purpose of aligning the leading edge of the sheet to be printed and are individually adjustable parallel to the direction of sheet advance.
Due to errors during the cutting of the sheets, the leading sheet edges are not always straight and/or are not always perpendicular to the lateral sheet edges.
In order to compensate for such error which may lead to faulty alignments in the printing press, it is known to align the front lay marks individually, corresponding to the course of the leading edge of the sheet. Such an alignment has been conventionally performed manually, while using an appropriate tool, such as a wrench. Such a procedure, however, has several disadvantages: it is time-consuming, it can be performed only while the press is at a standstill and, in particular, upon a displacement (adjustment) of any particular front lay mark, the operating person loses visual contact with that front lay mark to concentrate on the manual adjustment. As a result, it is not possible to make a direct verification whether the adjustment was sufficient or excessive. Also, it may occasionally occur that the wrong front lay mark is being adjusted.